1. Technical Field
The present invention relates to liquid ejecting head units used in liquid ejecting apparatuses such as ink jet recording apparatuses, manufacturing methods for liquid ejecting head units, and liquid ejecting apparatuses, and particularly relates to liquid ejecting head units, manufacturing methods for liquid ejecting head units, and liquid ejecting apparatuses in which multiple liquid ejecting heads can be attached with high positional precision.
2. Related Art
A liquid ejecting apparatus is an apparatus that includes a liquid ejecting head capable of ejecting a liquid as droplets, and that ejects various types of liquid from this liquid ejecting head. An image recording apparatus such as an ink jet recording apparatus (a printer) that includes an ink jet recording head (called simply a “recording head” hereinafter) and carries out recording by ejecting ink in liquid form through nozzles in the recording head as ink droplets can be given as a typical example of such a liquid ejecting apparatus. Meanwhile, in recent years, liquid ejecting apparatuses are being used in various types of manufacturing apparatuses such as display manufacturing apparatuses in addition to such image recording apparatuses.
In recent years, some such printers employ configurations in which multiple recording heads, each having a nozzle group made up of multiple nozzles arranged in rows, are arranged in and affixed to a head anchoring member such as a sub-carriage, thus configuring a single head unit (for example, see JP-A-2008-273109). This sub-carriage is a frame-shaped and flat plane-shaped member having openings provided in the areas in which the multiple recording heads are attached, and is manufactured from a synthetic resin in order to achieve a lighter weight. The recording heads are anchored to the sub-carriage using screws, having been positioned relative to the sub-carriage.
However, rotational momentum is applied to the sub-carriage when screwing the recording heads down onto the sub-carriage, and thus there has been the possibility that the frame-shaped sub-carriage will deform as a result. In particular, when sequentially attaching multiple recording heads to the sub-carriage, the rotational momentum is applied to the sub-carriage each time an individual recording head is affixed thereto, and thus the deformation of the sub-carriage will increase by that amount. Furthermore, even if the recording heads are attached and anchored having had their positions adjusted, the positions may be thrown off due to the deformation of the sub-carriage resulting from the rotational momentum when affixing the next recording heads to the sub-carriage after positioning the recording heads. As this deformation of the sub-carriage builds up, the relative positions of the recording heads become skewed, which in turn causes the relative positions between nozzles in respective recording heads to become skewed as well. As a result, variation occurs in the positions at which the ink lands upon the recording medium, which leads to a risk of a drop in the image quality of the recorded image and the like.
It should be noted that this type of problem is not limited to ink jet recording apparatuses provided with recording heads that eject ink; the same problem can occur in other liquid ejecting head units, and liquid ejecting apparatuses provided therewith, that employ a configuration in which multiple liquid ejecting heads are affixed to a frame-shaped head anchoring member such as the aforementioned sub-carriage.